The present invention relates to a melt-sealing device for extruders for the processing of thermoplastic polymers or rubber for sealing off the gear unit side of a conveying screw against high melt pressures within the extrusion chamber.
DE-AS 22 03 760 discloses a sealing device on the gear unit side of a rotating extruder screw. An intermediate chamber is arranged at the end of the screw on the gear unit side through which a highly pressurized additive is pressed into the actual extrusion chamber by a return thread in order to seal the extrusion chamber. A sealing on the gear unit side with regard to the additive cannot be obtained with a device of this type.
U.S. Pat. No. 2,835,514 discloses a sealing device that requires a multitude of complicated seals, which are subject to wear, for sealing the screw end on the gear unit side.